Digital pulse width modulator is an integral part in digitally controlled Direct Current to Direct Current (DC-DC) converter utilized in modern portable devices. This paper presents a new Digital Pulse Width Modulator...Digital pulse width modulator is an integral part in digitally controlled Direct Current to Direct Current (DC-DC) converter utilized in modern portable devices. This paper presents a new Digital Pulse Width Modulator (DPWM) architecture for DC-DC converter using mealy finite state machine with gray code encoding scheme and one hot encoding method to derive the variable duty cycle Pulse Width Modulation (PWM) signal without varying the clock frequency. To verify the proposed DPWM technique, the architecture with control input of six, five and four bits are implemented and the maximum operating frequency along with power consumption results is obtained for different Field Programmable Gate Array (FPGA) devices. The post layout timing results are presented showing that architecture can work with maximum frequency of 326 MHz and derive PWM signal of 3.59 MHz. Experimental results show the implementation of the proposed architecture in low-cost FPGA (Spartan 3A) with on-board oscillator clock frequency of 12 MHz which is multiplied internally by two with Digital Clock Manager (DCM) and derive the PWM signal of 1.5 MHz with a time resolution of 1 ps.展开更多
Vehicular Ad Hoc Network (VANET) is an emerging technology in which mobility management, continuous connectivity and security on data transmission between vehicles with high speed or during the change of topology of t...Vehicular Ad Hoc Network (VANET) is an emerging technology in which mobility management, continuous connectivity and security on data transmission between vehicles with high speed or during the change of topology of the network acts as a challenging exploration issue of Intelligent Transportation System (ITS) applications. This paper aims to formulate a ubiquitous connectivity to nodes by keeping the established connections before and after handover thereby minimizing the delay, packet loss and provide secured acknowledgement for handover. The Secured Efficient Fast Handover Multihoming Based NEMO+ (SEFMNEMO+) framework helps to optimize the NEMO+ scheme that supports multihomed network, handover and security. The predictive policy exchangemethod is used to update the future handover for minimizing the overhead delay and packet loss. The multihomed feature in NEMO+ supports efficient handover mechanism between heterogeneous networks when VANET connection fails. Public key cryptography provides the secure acknowledgement before handover i.e., the acknowledgement is encrypted with digital signature.展开更多
文摘Digital pulse width modulator is an integral part in digitally controlled Direct Current to Direct Current (DC-DC) converter utilized in modern portable devices. This paper presents a new Digital Pulse Width Modulator (DPWM) architecture for DC-DC converter using mealy finite state machine with gray code encoding scheme and one hot encoding method to derive the variable duty cycle Pulse Width Modulation (PWM) signal without varying the clock frequency. To verify the proposed DPWM technique, the architecture with control input of six, five and four bits are implemented and the maximum operating frequency along with power consumption results is obtained for different Field Programmable Gate Array (FPGA) devices. The post layout timing results are presented showing that architecture can work with maximum frequency of 326 MHz and derive PWM signal of 3.59 MHz. Experimental results show the implementation of the proposed architecture in low-cost FPGA (Spartan 3A) with on-board oscillator clock frequency of 12 MHz which is multiplied internally by two with Digital Clock Manager (DCM) and derive the PWM signal of 1.5 MHz with a time resolution of 1 ps.
文摘Vehicular Ad Hoc Network (VANET) is an emerging technology in which mobility management, continuous connectivity and security on data transmission between vehicles with high speed or during the change of topology of the network acts as a challenging exploration issue of Intelligent Transportation System (ITS) applications. This paper aims to formulate a ubiquitous connectivity to nodes by keeping the established connections before and after handover thereby minimizing the delay, packet loss and provide secured acknowledgement for handover. The Secured Efficient Fast Handover Multihoming Based NEMO+ (SEFMNEMO+) framework helps to optimize the NEMO+ scheme that supports multihomed network, handover and security. The predictive policy exchangemethod is used to update the future handover for minimizing the overhead delay and packet loss. The multihomed feature in NEMO+ supports efficient handover mechanism between heterogeneous networks when VANET connection fails. Public key cryptography provides the secure acknowledgement before handover i.e., the acknowledgement is encrypted with digital signature.
